Abstract: Conclusions
regarding the circumstances and behaviors elicited from the physical evidence
related to a crime (crime reconstruction) can infrequently be housed within
the confines of absolute certainty. This paper discusses the development
of Locard's Exchange Principle and historical and contemporary philosophies
surrounding crime reconstruction. It further discusses the fallacy of
assuming the integrity of physical evidence, and provides a logical foundation
for the concept of Evidence Dynamics. Evidence Dynamics refers to any
influence that changes, relocates, obscures, or obliterates physical evidence,
regardless of intent. Evidence Dynamics, it is further argued, come into
play during the interval that begins as evidence is being transferred,
and ends when the case is ultimately adjudicated. A discussion of the
various types of Evidence Dynamics is provided, followed up by demonstrative
examples from the authors' case files.

1W.
Jerry Chisum has been a criminalist since 1960. In October of 1998, he
retired from 30 years of service with the California Department of Justice
into private practice. He is currently serving as Vice-President of the
Academy of Behavioral Profiling, and is a member of their Board of Directors.
He can be reached for comment or consultation by contacting: URL: www.ncit.com; jchisum@profiling.org

2Brent
E. Turvey, MS is a forensic scientist, criminal profiler, and a full partner
of Knowledge Solutions, LLC. He is currently serving as Secretary of the
Academy of Behavioral Profiling, and is a member of their Board of Directors.
He can be reached for comment, consultation or reprints of this article
by contacting: Knowledge Solutions, 1961 Main St., PMB 221, Watsonville,
CA 95076; Phone (831)786-9238; bturvey@corpus-delicti.com.

Of all responsibilities
shouldered by the forensic scientist, the reconstruction of the circumstances
and behaviors involved in a crime is one of the most important. In conjunction
with agreeable witness accounts, a crime reconstruction may be a powerful
instrument of corroboration. In the face of conflicted witness accounts,
it may provide an objective view that points to one possibility over another.
In the absence of witness accounts, it may be used to investigate and
establish the actions that occurred at the scene of a crime. The role
that crime reconstruction can play investigatively and legally should
never be underestimated.

Because of the varied
evidence and circumstances involved, the ability to reconstruct crime
requires broad forensic knowledge, an objective if not conservative disposition
towards the examination and interpretation of evidence, and what the fictional
Dr. Watson of Sherlock Holmes fame referred to as a "peculiar
facility for deduction." [9]

Despite its importance
to investigative and legal venues, crime reconstruction is often performed
inappropriately by the unknowledgeable and overconfident. This includes
those with little knowledge of, or training in, the peculiarities of physical
evidence and the forensic sciences. Those testifying as experts in the
area of crime reconstruction routinely cite as a premise, for otherwise
unproven opinions, the sum of their education, training, and experience.
It may be the case that this is offered in the place of facts from the
case file. This practice is regarded as illegitimate for a forensic examiner.
"Experience should not make the expert less responsible, but rather
more responsible for justifying an opinion with defensible scientific
facts." [12]

Conclusions regarding
the circumstances and behaviors elicited from the physical evidence related
to a crime can infrequently be housed within the confines of absolute
certainty. It is often an intensive process with imprecise results containing
evidentiary holes, sequential gaps, and alternate possibilities. This
does not suggest that crime reconstruction efforts lack investigative
or legal utility. The utility of crime reconstruction is by no means bound
to any predisposition for certainty. Rather, its utility is more often
found in establishing the general circumstances of a crime, demonstrating
links between victims, suspects, and offenders, corroboration of witness
statements, providing investigative leads, and identifying potential suspects.
[8]

Further still, it
is often the case that what the physical evidence excludes, fails to establish,
or equivocates, is actually of great investigative and legal importance.
Forensic analysis in general, and crime reconstruction in particular,
is concerned with those conclusions that can be logically drawn from the
evidence, as well as with those that cannot. As such, the consideration
of both the strengths and limitations of available physical evidence are
an important part of crime reconstruction. It is with these considerations
in mind that we begin our discussion of the relationship between Locard's
Exchange Principle, Crime Reconstruction, Evidence Dynamics and
their implications to forensic examinations.

The Development of
Locard's Exchange PrincipleAlphonse
Bertillon developed one of the first scientific systems of documenting
personal identification in Paris in the late 1800s [3, 11]. In 1879, Msr.
Bertillon began his career when he was appointed clerk in the Premier
Bureau of the Prefecture of Police [10]. The sheer volume of the files
required organization. He used the measurement system that his father,
a physical anthropologist, used to organize skeletal material. Bertillons
genius was in adapting this method to living persons and establishing
a record system. The method referred to ultimately as Bertillonage
used the relatively simple procedure of taking a series of body measurements,
noting other physical characteristics, and placing this information on
a single identification card in a police file [3]. As the method developed
he started adding photographs of the individual to the files. Bertillonage
was a significant advancement in terms of providing a useful database
of criminals for criminal investigators.

Bertillon was motivated
to develop his methods not only by the desire to assist in the tracking
of criminals and their behavior, but also by a personal belief that everything
that "lived and moved under heaven" was somehow unique [10].
His was something of a radical notion in criminal investigation at the
time: that science and logic should be used to investigate and solve crime.
As Msr. Bertillon's biographer stated:

The methods of the
French police in that year of grace 1879 had changed very little in
principle from those initiated by that criminal turned policeman, the
brilliant and unscrupulous [Eugene] Vidocq. They consisted in the liberal
use of the police informer, and agent provocateur. [10]

Bertillonage was employed
to identify criminals by law enforcement for at least two decades, until
it was replaced by the use of fingerprints. In 1891, Dr. Hans Gross,
an Austrian Magistrate and Professor of Criminology, made the following
observation, "The advantages of finger-prints over the Bertillon
system have become so well established that the latter can with perfect
safety be dispensed with altogether as unnecessary for the purposes of
identification."[5]

However, Bertillonage
was not the limit of Msr. Bertillon's contribution to the forensic sciences,
nor was it his most significant. His dedication to precise measurements
and the use of photography led to a combination of the two practices beyond
criminal identification. Bertillon assisted in the development and practice
of forensic photography by introducing a measuring scale with the persons
and objects of evidence that he photographed [10]. The usefulness of this
practice soon became apparent. He was routinely sent out with investigators
to document crime scenes. He would photograph the bodies of victims, their
relationship to significant items of evidence in the scene, as well as
the position, size, nature and extent of other physical evidence including
footprints, stains, toolmarks, and points of entry [10]. Until the development
of this practice, criminal investigators and the courts relied upon sketches
and notes of varying precision for their understanding of the context
of a crime. That is, if any record were made of a crime scene at all.

Bertillon also instructed
and influenced several students, including Dr. Edmond Locard, whose
work formed the basis for what is widely regarded as a cornerstone of
the forensic sciences, Locard's Exchange Principle (for discussion,
see: [3], [6] & [11]). Dr. Locard, like Dr. Hans Gross and Msr. Bertillon
before him, advocated the application of scientific methods and logic
to criminal investigation and identification [11]. As stated by Dr.
John Thornton, a criminalist and a former professor of forensic science
at the University of California, Berkeley:

Forensic scientists
have almost universally accepted the Locard Exchange Principle.
This doctrine was enunciated early in the 20th Century by Edmund Locard,
the director of the first crime laboratory, in Lyon, France. Locard's
Exchange Principle states that with contact between two items, there
will be an exchange [12]

Due in no small part
to Mr. Bertillon's influence, it was Dr. Locard's belief and assertion
that when any person comes into contact with an object or another person,
a cross-transfer of physical evidence occurs [11]. By recognizing, documenting,
and examining the nature and extent of this evidentiary exchange, Locard
observed that criminals could be associated with particular locations,
items of evidence and victims. The detection of the exchanged materials
is interpreted to mean that the two objects were in contact. This is the
cause and effect principle reversed; the effect is observed and the cause
is concluded.

Forensic scientists
also recognize that the nature and extent of this exchange can be used
not only to associate a criminal with locations, items, and victims, but
with specific actions as well [2, 3, 11, 13, 14].

Crime ReconstructionCrime reconstruction
is "the determination of the actions surrounding the commission of
a crime." [1] Careful and competent examination of the physical evidence
the documentation of the crime scene allows for this determination. The
systematic documentation and recording of the crime scene is required
for this analysis. The photographic documentation as established by Bertillon
is a necessity for crime reconstruction. The veracity of statements by
witnesses, victims, and suspects can be established by reconstruction.

Modern methods of
crime reconstruction owe themselves to a strong history marked by rigorous
analytical thought and forensic application. The collective work of Alphonse
Bertillon, Dr. Hans Gross, and Dr. Edmond Locard are no small part of
this history. Enduring themes include the importance of physical evidence,
objectivity, the necessary employment of logic, and viewing witness, victim,
and offender statements with suspicion.

Just before the turn
of the century, Dr. Hans Gross, in discussing how a crime should be reconstructed,
argued for strict objectivity and a logical, sequential, frame by frame
analysis on the part of criminal investigators:

Nothing can be known
if nothing has happened

in the profession
of the criminal expert everything bearing the least trace of exaggeration
must be removed in the most energetic and conscientious manner; otherwise,
the Investigating Officer will become an expert unworthy of his service
and even dangerous to humanity.

all of the
circumstances of the crime must be clearly taken into account and submitted
to a strict logical examination from their commencement to their last
stage. If at a given moment something has not been explained, suspicion
is justified and a pause must be made at the point where the logical
sequence is broken...[5].

Dr. Gross also decried
the heavy reliance of criminal investigators and the courts on witness
accounts, strongly advocating the use of physical evidence, writing:

The progress of
criminology means less trust in witnesses and more in real proofs. [9]

the criminologist
re-creates the criminal from traces the latter leaves behind, just as
the archaeologist reconstructs prehistoric beings from his finds. [9]

Dr. Theodore Reik,
a Professor of Psychoanalysis at Vienna University, an early disciple
of Dr. Sigmund Freud, also argued for the use of objectivity and logic
in the investigation of crime and criminals:

The object of the
criminologist's reasoning is knowledge of a material event and the finding
of an unknown person

Cool, objective
thought, re-examination of facts according to the rules of logic, raisonnement
(Locard) is the pivot of the detectives mental process. [9]

In the second half
of this century, the late Dr. Paul Kirk, Professor of Criminalistics at
the University of California, Berkeley, shared the views of Drs. Gross
and Locard regarding issues of witnesses, physical evidence, and crime
reconstruction, arguing:

the utilization
of physical evidence is critical to the solution of most crime. No longer
may the police depend upon the confession, as they have done to a large
extent in the past. The eyewitness has never been dependable, as any
experienced investigator or attorney knows quite well. Only physical
evidence is infallible, and then only when it is properly recognized,
studied, and interpreted. [13]

Dr. Kirk further argued,
supporting the validity of Locard's Exchange Principle, the importance
of transfer evidence to crime reconstruction:

Wherever he steps,
whatever he touches, whatever he leaves, even unconsciously, will serve
as silent witness against him. Not only his fingerprints or his footprints,
but his hair, the fibers from his clothing, the glass he breaks, the
tool mark he leaves, the paint he scratches, the blood or semen he deposits
or collects. All of these and more bear mute witness against him. This
is evidence that does not forget. [13]

However, Dr. Kirk
also argued for caution in the interpretation of evidentiary exchanges.
In this brief discussion on establishing the identification of an object's
source, he makes it clear that it is an endeavor with inherent hazards
under even the best conditions.

In the examination
and interpretation of physical evidence, the distinction between identification
and individuation must always be clearly made, to facilitate the real
purpose of the criminalist: to determine the identity of source. That
is, two items of evidence, one known and the other unknown, must be
identified as having a common origin. On the witness stand, the criminalist
must be willing to admit that absolute identity is impossible to establish.
Identity of source, on the other hand, often may be established unequivocally,
and no witness who has established it need ever back down in the face
of cross-examination.

It is precisely
here that the greatest caution must be exercised. The inept or biased
witness may readily testify to an identity, or to a type of identity,
that does not actually exist. This can come about because of his confusion
as to the nature of identity, his inability to evaluate the results
of his observations, or because his general technical deficiencies preclude
meaningful results. [13]

Dr. Henry Lee, former
Director of the Connecticut State Police Crime Laboratory, also advocates
a combination of both physical evidence and logic by forensic scientists
engaging in reconstruction:

Reconstruction not
only involves the scientific scene analysis, interpretation of scene
pattern evidence and laboratory examination of physical evidence, but
also involves systematic study of related information and the logical
formulation of a theory. [7]

Dr. John Thornton,
previously mentioned, a student of Dr. Kirk, describes the mechanics of
the logic that should be employed by forensic scientists when undertaking
a forensic examination:

Induction is a type
of inference that proceeds from a set of specific observations to a
generalization, called a premise. This premise is a working assumption,
but it may not always be valid. A deduction, on the other hand, proceeds
from a generalization to a specific case, and that is generally what
happens in forensic practice. Providing that the premise is valid, the
deduction will be valid. But knowing whether the premise is valid is
the name of the game here; it is not difficult to be fooled into thinking
that one's premises are valid when they are not.

Forensic scientists
have, for the most part, treated induction and deduction rather casually.
They have failed to recognize that induction, not deduction, is the
counterpart of hypothesis testing and theory revision. too often
a hypothesis is declared as a deductive conclusion, when in fact it
is a statement awaiting verification through testing. [12]

The physical evidence
left behind at the crime scene plays a crucial role in reconstructing
the events that took place surrounding the crime The collection
and documentation of physical evidence is the foundation of a reconstruction.
[11]

One of the authors,
also a student of Dr. Kirk, makes a cogent forensic argument regarding
the potential value of crime reconstruction to the court in terms of establishing
what has actually happened in a given case:

The prosecutor seeks
to convict the defendant by making the crime more heinous in nature.
The defense seeks to exonerate the defendant. Both theorize about how
the crime occurred with different objectives. Both cannot be correct
and, lacking a reconstruction, both are probably wrong. The theories
are alternatives and should be examined against the evidence

Any theory of the
crime must be based on logic  explaining the physical evidence
and its location at the scene. It is through such analysis that the
behavior of the perpetrator is revealed...[1]

Crime reconstruction,
as argued, involves examining the available physical evidence, those materials
left at or removed from the scene, victim, or offender. These materials
are used by the forensic scientist establish to contact between the suspect
and victim or scene

according to the principle
proposed Dr. Locard. These forensically established contacts are then
considered in light of available and reliable witness, victim, and offender
statements. From this, theories regarding the circumstances of the crime
can be generated and falsified by logically applying the information of
the established facts of the case. Left standing, ideally, will be legitimate,
logical conclusions regarding the actions surrounding the commission of
the crime or as put by the fictional Sherlock Holmes in the Sign of
Four, "when you have eliminated the impossible, whatever
remains, however improbable, must be the truth."

The Assumption of
IntegrityThe process
of crime reconstruction is often built on the assumption that evidence
left behind at a crime scene, which has been recognized, documented, collected,
identified, compared, individuated, and reconstructed, is pristine. This
assumption involves the belief that the process of taping off an area,
limiting access, and setting about the task of taking pictures and making
measurements ensures the integrity of the evidence found within. Subsequently,
any conclusions reached through forensic examinations and reconstructions
of that evidence are assumed to be a reliable lens through which to view
the crime. This assumption is not always accurate.

Even though a reliable
chain of evidence may be established1, physical evidence
may have been altered prior to or during its collection and examination.
Unless the integrity of the evidence can be reliably established, and
legitimate evidentiary influences accounted for, the documentation of
a chain of evidence, by itself, does not provide acceptable ground upon
which to build reliable forensic conclusions.

Consideration of evidentiary
influences, or Evidence Dynamics, is a necessary part of the crime
reconstruction process.

Evidence DynamicsCrime reconstruction
efforts are concerned with examining the effects or results of actions
done in the commission of the crime. As Dr. Gross was fond of saying,
"What is effect and what is cause?" [9] This is answered by
the use of logic and forensic axioms such as Locard's Exchange Principle.
However, often missing from that analysis is a consideration of those
influences that can change physical evidence prior to or as a result of
its examination.

The general term Evidence
Dynamics has been developed by the authors to refer to any influence
that changes, relocates, obscures, or obliterates physical evidence, regardless
of intent. Evidence Dynamics comes into play during the interval
that begins as evidence is being transferred, and ends when the case is
ultimately adjudicated. For those who are familiar with such evidentiary
influences, and account for them in their analysis, this terminology is
intended to provide a necessary and useful descriptor. An appreciation
of Evidence Dynamics on what can be concluded from the physical
evidence is requisite, and often pivotal, to the reconstruction process.

In the interpretation
of Evidence Dynamics, two questions require attention. First, is
there an item of evidence that has been demonstrably influenced between
the time of the crime and the time of examination? If an item of evidence
has been moved, changed, or obscured, then this must be factored into
the examiner's analysis in terms of when and how. Second, is there evidence
of a circumstance that could have obliterated or influenced evidence?
Forensic scientists can only include in their analyses those things for
which evidence exists. However, if there is no reasonable suggestion of
circumstances that could have influenced or obliterated evidence, then
the examiner should not assume that they occurred.

There are many possible
influences on Evidence Dynamics that should be considered as evidence
is examined. A brief list, not meant to be all-inclusive, is provided
below.

Offender actions:
The actions of an offender during the commission of their crime and the
post-offense interval influence the nature and quality of evidence that
is left behind.

These can include
Precautionary Acts, Ritual or Fantasy, and Staging.
Precautionary Acts involving physical evidence are behaviors committed
by an offender before, during, or after an offense that are consciously
intended to confuse, hamper, or defeat investigative or forensic efforts
for the purposes of concealing their identity, their connection to the
crime, or the crime itself [15]. Staging of the crime scene is
a specific type of precautionary act that is done to deflect suspicion
away from the offender. Staging often involves the addition of,
removal of, and manipulation of objects in the crime scene to change the
apparent "motive" of the crime. [15] Ritual or Fantasy
may also influence the offenders actions during a crime, and can
include such things as postmortem mutilation, necrophilia, and purposeful
arrangement of a body or items in a scene. [15]

Victim actions:
The victims activities prior to a crime may result in artifacts
that are mistaken for evidence. The actions of a victim during an attack
and in the post-offense interval can influence the nature and quality
of evidence that is left behind. This includes defensive actions, such
as struggling, fighting, and running, which can relocate transfer evidence,
causing secondary transfer. The victims actions may also include
cleaning up a location or their person after an attack.

Secondary Transfer:
Transfer evidence, as we have established, is produced by contact between
persons and objects [2, 8]. Secondary transfer refers to an exchange of
evidence between objects or persons that occurs subsequent to an original
exchange, unassociated with the circumstances that produced the original
exchange2.

Witnesses:
The actions of witnesses in the post-offense interval can influence the
nature and quality of evidence that is left behind. This includes actions
taken to preserve victim dignity, as well as the deliberate theft of items
from the scene upon discovery of an incapacitated or deceased victim.

Weather/ Climate:
The weather or climate of a crime can influence the nature and quality
of all manner of evidence that is left behind. This includes the destruction
or obliteration of evidence by all manner of weather, as well as the effects
of weather and climate on rates of body and biological transfer evidence
decomposition.

Decomposition:
Naturally occurring rates of decomposition, over time, can obscure, obliterate
or mimic evidence of injury to a body. The clothing from a decomposed
body will normally receive less attention for trace or transfer evidence.

Insect Activity:
The actions of flies, ants, beetles, and other insects can obliterate
the wounds on a body. They may also move, remove or destroy the transfer
evidence.

Animal Predation:
The feeding activities of all manner of indigenous wildlife from mice
to coyotes and bears can relocate evidence, obliterate patterns, and further
obscure, obliterate or mimic evidence of criminal injury to a body.

Fire: In cases
were fire is involved, intentional or otherwise, the result can be the
obscuring of all manner of physical evidence related to criminal activities,
as well as its potential destruction. The evidence showing the actions
of the offender regarding the primary offense are obscured if not eliminated
by the subsequent arson. Evidence of the arson may remain.

Fire Suppression
Efforts: In cases were fire is involved, there may be suppression
efforts made. These efforts typically involve the use of high-pressure
water, heavy hoses, perhaps chemicals, and firemen. Any of these, alone
or in concert, can relocate the evidence, obliterate patterns, cause potentially
misleading transfers, and/or add artifact-evidence3, to the
scene.

Police: The
duty of the first officer on the scene is to protect life, not to preserve
evidence. They must establish that the scene is secure from further attacks.
Their actions may relocate evidence, obliterate patterns, cause transfers,
and add artifact-evidence to the scene.

Emergency Medical
Technicians: The actions of emergency medical personnel engaged in
life saving activities in a crime may relocate evidence, obliterate patterns,
cause transfers, and add artifacts mistaken as evidence. As well, they
can add therapeutic injuries to the victim.

Scene Technicians:
The actions of technicians working in the physical evidence recognition,
preservation, documentation, and collection phases in a crime scene are
expected to remove evidence without obliterating patterns, causing potentially
misleading transfers, and adding artifact-evidence to the scene. The technicians
must thoroughly document the scene prior to entering so the changes that
occur are obvious.

Forensic Scientists:
The actions of forensic scientists will also remove evidence, obliterate
patterns, may cause potentially misleading transfers, and add artifact-evidence
to the scene. This can occur by virtue of improper storage or destructive
analytical techniques, or the addition of transfer and/or pattern evidence
to a victim's body or clothing during transport and/or storage.

Coroners: The
actions of the coroner in removing the body from the scene can move evidence,
obliterate patterns, cause potentially misleading transfer, and add artifact-evidence
to the scene. This includes the physical removal of the body from the
location where it was discovered, the placement of the body into a "body
bag," and the process of transporting the body from the scene. These
actions will change pattern evidence on the clothing of the victim and
may destroy potential valuable transfer evidence.

Case ExamplesThe following
case examples have been taken from the authors case files:

Example #1
- Fire and Suppression EffortsA young female arrived at her older boyfriend's home, where he lived
with his elderly mother and two teenage children. A confrontation ensued.
The boyfriend and his mother, who were the only ones home at the time,
were both killed, dying of exsanguination from multiple gunshot wounds.

The boyfriend's
body was found outside of the residence with an associated blood trail.
After the girlfriend removed some items of value she set both the house
and the body of the boyfriend on fire.

Some of the actions
and circumstances involved in the crime were evident, given the body
outside of the home, associated transfer evidence, and blood patterns.
However, a sequential reconstruction of the shots fired within the house,
as well as the relative positions of the shooter and the victims, was
significantly impaired. This was due to the movement and destruction
of walls, furniture, flooring, household items, the body of the mother,
and blood evidence in the scene. A crime analysis of the case reads
in part:

precise
reconstruction efforts are hampered in this case due to the numerous
destructive and evidence-altering variables that were imposed upon
the scene in the interval after the deaths occurred and before it
was safe for forensic efforts to take priority. These destructive
and evidence-altering variables and elements, documented in part by
a video made of this scene during and after suppression efforts were
engaged, include, but are not limited to:

the destructive
nature of the fire itself, which involved both stories and many
rooms in the house;

the destructive
nature of the suppression efforts, which involved water being pumped
into the home at approximately 1000 gallons per minute, the destruction
and movement of items in the home for both suppression and salvage
purposes, as well as unintentional damage that may have been caused
by heavy fire hoses in various locations within the home;

the number
of personnel venturing in and out of the home during and after suppression
efforts, which some estimate may have been more that 50 individuals.

Example #2
- Decomposition & Insect ActivityAn adolescent female was missing for approximately two weeks before
investigators found her body. It was located in a slightly concealed
area of foliage behind an unoccupied residence. Her deceased body had
been placed inside of a piece of recently discarded carpeting, beneath
a heavy metal water tank, and then covered by several more layers of
older discarded carpeting.

According to the
autopsy report, and visible in the autopsy photos, the victim's underwear
was found in her mouth. The cause of death was determined to be "asphyxia
by gagging" possibly in combination with a violent blow to the
victim's jaw as evidenced by a fracture to the mandible.

The question arose
as to whether there was evidence of manual or ligature strangulation.
Due to the overall advanced state of decomposition, and the fact that
maggots had consumed the soft tissue associated with the neck, a determination
on this issue was not possible. In the absence of evidence to examine,
one cannot make a legitimate determination as to whether or not manual
or ligature strangulation occurred. This did not exclude the possibility
that it may have occurred; merely that it could not be established and
therefore should not be assumed for the purposes of analysis.

Example #3
- Secondary Transfer and Scene TechniciansThe body of an adolescent female was found on a couch in her home
where she lived with her mother and younger brother. She was wearing
only a shirt and bra at the time of discovery. She was determined to
have died of "asphyxia secondary to manual strangulation."
She had a history of sexual abuse, suggested by the absence of her hymen
and numerous anal scars, as well as a history of promiscuity. The DNA
of one of her mother's lovers was found on her perineum, in the form
of sperm.

Given the location
and circumstances of the crime, the precise conditions of this exchange
could not be reliably established. One possibility is that the suspect
was engaged in some form of sexual activity with the victim, and that
sperm transferred to her perineum as a result. However, the suspect
and the victim's mother had sexual relations in the mother's bed, where
the victim had been playing previously with her brother. There were
also reports that the suspect and the victim's mother may have had sexual
relations on the couch, were the victim would have been sitting. Additionally,
a review of the crime scene video shows several evidence technicians
moving evidence around on the couch and other locations, and then touching
the victim's body in multiple locations, examining her body as it is
being photographed, with and without gloves.

Given these circumstances,
and the victim's history, the following are potential evidence transfer
relationships in this case:

From the suspect
to the victim during a forced sexual assault;

From the suspect
to the victim during a consensual (but unlawful) sexual encounter;

From the couch
to the victim's perineum;

From the mother's
bed to the victim's perineum;

From the scene
technician's fingers to the victim's perineum

Example #
4 - Emergency Medical TechniciansA youth was stabbed several times by rival gang members. He ran
for a home but collapsed in the walkway. A photo of the scene taken
prior to the arrival of the EMT team shows a blood trail and that the
victim was lying face down. Subsequent photos show the 5 EMTs working
on the body on his back. He had been rolled over onto the blood pool.
It became impossible for bloodstain pattern interpretation to be used
to reconstruct the events leading to the death of the youth.

Example #
5  Coroner ActivitiesPhotos taken of the deceased showed isolated bloodstain patterns
on the clothing of the victim of a rape homicide. She had been sexually
assaulted and her throat was cut. The patterns on her panties appeared
to be bloody transfers from a hand. The coroner refused to remove the
clothing at the scene. When the panties were submitted to the laboratory
they were soaked in the victims blood from transporting her in
the body bag. The patterns were destroyed as well as making it impossible
to isolate the stains for identification purposes.

Example #
6  Victim ActivitiesIn this case the victims actions prior to a crime caused "false
evidence" to be present. A woman had sex with her boyfriend in
his vehicle. He dropped her off at her apartment. As she enters her
bedroom she surprises a burglar. A struggle ensued causing tears in
her clothing before the burglar strangled her and fled. The boyfriend
is suspected of the "rape/homicide." His DNA is found in her
vagina. This would be considered proof of his guilt in many courts.

Fortunately, the
boyfriend had an alibi; he was stopped for DUI a couple of blocks from
the house. He was in police custody during the time the screams were
heard by the neighbors.

Example #
7  Family Activities
The body of an elderly man was found "in his bed." Upon examination,
strangulation marks were found on his neck. These marks were consistent
with a hanging. When questioned the family admitted that he had hanged
himself. They didnt want the "shame on their family,"
so they had cut him down, changed his clothing and put him to bed. The
evidence was destroyed for cultural reasons.

ConclusionsThe failure
to consider Evidence Dynamics as a part of any crime reconstruction
process has the potential to provide for misinterpretations of physical
evidence, and inaccurate or incomplete crime reconstructions. Any subsequent
use of the reconstruction for investigations, trial or behavioral analysis
would have a diminished foundation and relevance, compounding the harm
in legal, investigative and academic venues. It is the responsibility
of the forensic scientist to perform reconstructions of the circumstances
and behaviors involved in a crimes with care, and to be aware of the possibility
of Evidence Dynamics, in order that opinions regarding reconstruction
of the crime reflect the most informed and accurate rendering of the evidence.

Notes

1. For
discussions, see: [3], [4], [7], & [11]

2.
For example, an offender wearing a wool sweater kills a female in her
home. The offender leaves a number of wool fibers behind on the victim's
body. The victim's neighbor hears the struggle and discovers the body.
While attempting to revive the victim, several of the wool fibers transfer
onto his clothing. When the clothing is examined in the laboratory,
wool fibers foreign to the location are found on both the victim and
his clothing, causing investigators to suspect him of the crime. Unless
the circumstances of the crime are thoroughly investigated, and the
possibility of secondary transfer explored, the neighbor may be wrongfully
charged with the crime.

3.
Artifact-evidence is any change in crime scene evidence or addition
to crime scene evidence that can mislead one into inferring that the
"evidence" is related to the commission of the crime.

Thornton, John
I., "The General Assumptions And Rationale Of Forensic Identification,"
in David L. Faigman, David H. Kaye, Michael J. Saks, & Joseph Sanders,
Editors, Modern Scientific Evidence: The Law And Science Of Expert
Testimony, Volume 2, (St. Paul: West Publishing Co., 1997)